crescent



' Filed Oct 17, 1952 Jan. 24, 1956 A. CRESCENT 2,

ADJUSTABLE CHAIR WITH INVISIBLE MECHANISM 2 Sheets-Sheet 1 Jan. 24, 1956 H. A. CRESCENT 2,732,006

ADJUSTABLE CHAIR WITH INVISIBLE MECHANISM Filed Oct. 17, 1952 2 Sheets-Sheet 2 United States PatentO ADJUSTABLE CHAIR WITH INVISIBLE MECHANISM Henri Alexandre Crescent, Arques-la-Bataille (Seine Inferieure), France Application October 17, 1952, Serial No. 315,382 Claims priority, application France October 30, 1951 2 Claims. (Cl. 155-88) My invention relates to an adjustable chair of the X- legged type, i. e. of the type comprising two cross-braced standards, the upper portions of which constitute side members for the back of the chair and the lower portions of which constitute the front legs of said chair, two crossbraced rear legs each articulated on the mating front leg in a scissor fashion and a seat member articulated forwards on the upper ends of said rear legs and the rear edge of which is adjustable along the above mentioned standards, between a certain number of positions, each one of which corresponds to a given angular relative position between the back and the seat of the chair thus permitting multiple uses of a same chair.

7 Known adjustable seats of the type described are usually provided with an unesthetic apparent mechanism which makes their use indoors unsuitable.

One object of my invention is to provide an adjustable chair having a normally hidden mechanism and so designed as to offer the usual aspect of an indoor non-adjustable chair.

On the other hand, most of the known mechanisms used in adjustable chairs are not practical to manipulate, while most of them are not safe, due to the fact that the means used to lock the chair in a given position are not automatically located in said position so that they can escape, e. g. when the seat is raised from the ground to be displaced or even when the user sits on the chair.

Another object of my invention is to provide in an adjustable chair of the type described, an improved adjusting mechanism which, while being of a very simple and therefore cheap construction, ensures an automatic elastic location of the locking means in each position of the seat.

Still a further object of my invention is to provide an adjustable chair mechanism, the manipulation of whichis extremely simplified since it only requires a downwards pushing action to bring the seat from any adjusted position to any other one, said downwards pushing action being, of course, exerted on two different members of the chair according as whether the seat is to be raised or lowered.

A further object of my invention is to provide an adjustable chair mechanism in which one single member is made of the same wood as the legs and the seat, and ensures at the same time three different functions viz. concealing the rest of the mechanism, ensuring by its own elasticity the safe location of the locking means in any desired position of the seat and raising automatically, by a slope guiding effect, said locking means to an upper position (provided, of course, said means have not reached their uppermost position) when a downwards pushing action is exerted on the rear lower portion of the rear legs of the chair, the same being so held as to rest only on its front legs.

Other objects, features and advantages of my invention will be apparent from the following detailed description, together with the accompanying drawings, submitted for purposes of illustration only and not intended to define 2,732,006 Patented Jan. 24, 1956- the scope of the invention, reference being had for that purpose to the subjoined claims.

In these drawings:

Fig. 1 is a perspective view of an embodiment of the adjustable chair according to the invention, shown in its uppermost position.

Fig. 2 is a perspective view corresponding to Fig. 1, but showing the chair after adjustment to another position.

Fig. 3 is a detailed perspective view showing the articulation of one rear leg under the seat of the chair.

Fig. 4 is a detail partly sectional view along line 4-4 of Fig. 1.

Fig. 5 is a sectional view along line 5-5 of Fig. 2.

Fig. 6 is a detail perspective view showing the articulation of a rear leg on the lowest cross-member of the back.

As shown in the drawings, the adjustable chair according to the invention comprises a pair of front legs 1 extended upwards, as shown at 2, so as to constitute the side members of the back rest of the chair. The latter is completed, in the example shown, by cross-braces 3,. 4 and 8 rigidly assembling together standards 12 andv by laths 5. The rear legs 6 are articulated, each on one. front leg 1 in a scissor fashion, as shown at 7, about the rounded ends of cross-member 8, as described in detail hereunder with reference to Fig. 6. Another cross-member 9 interconnects the lower portions of legs 6, to make the assembly more rigid and to enable controlling in one direction the adjusting mechanism according to the invention, as explained hereunder. The seat of the chair is constituted by a fiat member 10 articulated near its front edge on the upper ends of the rear legs 6. In this exampie, as shown more clearly in Fig. 3, said rear leg upper ends are provided with rounded upright tips 11. An articulation rod 12 is supported at each end in a suitable hole on a bracket 13 secured by screws 14 to the lower face of the seat member 10. The mid-portion of that portion of bracket 13 which is secured under the seat mem ber 10, is cut out and folded at right-angles to constitute an abutment 15 for the end of rod 12. The rounded tips 11 of the rear legs 6 are provided with grooves 16 adapted to receive rod 12. The latter is retained in said grooves by incurved metal strips 17 secured on the tip 11 of each front leg by means of screws 18. Rod 12 thus constitutes both a cross-member for the upper end of rear legs 6 and an articulation axis pivoted in brackets 13.

Suitable articulation means are provided to adjustably secure the rear edge of the seat member 10 at different levels along the standards 1-2.

In the example shown, the seat member 10 is adjustable at three different relative angular positions with respect to the back of the chair. For this purpose, the inner face of each standard 1--2 is provided with three notches 19a, 19b, 19c opening rearwards and downwards, each located at a same horizontal level as the corresponding notch ofthe other standard and the rear edge of the seat member 10 is provided with a pair of pins having theiraxes on a same horizontal and adapted to be engaged simultaneously in both notches of a same level. In the example shown, said pins are constituted by the protruding ends 20 of rods secured in the bored ends of a horizontal bar 21 which ensures, as described hereunder, lowering of the seat. On the other hand, the bar 21 is secured on the rear edge of the seat member 10 through lugs 22 integral with the latter and adapted to slide along the inner faces of the standards 12. A sufficient spacing is provided between the bar 21 and the rear edge of the seat member 10 to accommodate the laths 5 of the back so that the whole assembly of the seat member 10, bar 21 and pins 20 can be displaced between a rearmost position in which said assembly is free- 1y slidable along said laths and the standards and a foremost position in which pins 20 are engaged home into a level of notches.

According to an essential feature of the invention, the adjusting mechanism so far described, is normally hidden so that the chair offers, when adjusted in a given position, the same esthetic aspect as if it were not provided with such a mechanism. For this purpose, the notches 19 instead of opening directly in the rear faces of the standards, are cut in the bottom surfaces of longitudinal right angular grooves 23 provided in said rear faces and bars 24 made of same material as the. standards are adapted to fit into said grooves when the adjusting mechanism is set into a given position, so as to reconstitute the original outline of the standards. In the example shown, each bar 24 is secured on the relevant'standard only near its lower end, as by means of a screw 25.

According to another feature of the invention, the natural elasticity of the bars 24 is used to locate elastically pins 20 in the different levels of notches, and according to still another feature of the invention, the oblique position of said bars, with respect to the vertical, ensures automatic raising of the pins 29 (when the same are brought out of a given level of notches under a sufficient rearwards stress exerted on the seat member as explained hereunder) up to the next level of notches where pins are then automatically engaged and located under the action of the above mentioned natural elasticity of the bars 24.

It is clear that when the user sits on the chair or when the chair is raised above the ground to be displaced, the X-articulation arrangement of the legs and rearwards and downwards orientation of the notches maintain pins 20 in the bottom of the notches. However, in order to ensure an additional safety, in particular against unlocking due, for instance, to the frequent motion of a user, who, sitting on the chair and raising himself to bring his chair forward abuts the front legs of the chair against his heels, bars 24 are interconnected at their upper ends through a cross-member 26 (see Figs. 1 and 2) and said cross-member 26 can be locked by means of a latch 27 articulated at 28 on the cross-member 4 of the back. As shown in detail in Fig. 6, the lowest cross-member 8 of the back is provided with trunnions 7 on which are pivoted the rear legs 6 of the chair, the outer ends of trunnions 7 being secured on the front legs 1. To permit easy dismantling of rear legs 6, each one of the same is provided with a cut-off portion 29 the bottom 30 of which is located in the mid-thickness plane of rear leg 6. A semicircular groove 31 is provided in bottom 30 and a block 32 provided with a corresponding semi-circular groove 33 is introduced into cut-01f portion 29 after the rear leg 6 has been engaged bythe semi-circular groove 31 on trunnion 7. In the example shown, due to the oblique shape of the lateral assembling surfaces of block 32 and rear leg 6 a single screw 34 is sufficient for securing said block on said leg.

The operation of the mechanism described above is remarkably simple.

The seat being, for example, in its uppermostposition, as shown in Fig. 1 which corresponds to the largest angular relative position between the seat and the back of the chair, if one wishes to set the chair into a more comfortable position, it suifices to pivot the latch 27 so as to unlock the assembly comprising the wood bars 24 and cross-member 26. The chair is then slightly tilted forwards so as to rest on its front legs 1 only; it then suffices to draw bar 21 slightly rearwards so as to disengage the pins 20 from the upper level of notches against the elastic action of bars 24 and then to push bar 21 downwards until it is automatically engaged in a snap manner in the next lower level of notches under said elastic action; crossmember 26 is then locked under latch 27, anew.

To raise the seat to an upper level of notches (if any), it is still simpler. As a matter of fact, after having unlocked cross-member 26, it suffices to push the lower cross-member 9 of the rear legs downwards (seat being of course held as previously on its front legs only) whereupon, due to the cam action of the bars 24 which has been already explained, the pins 20 will be raised automatically as soon as the same are brought out of a given level of notches.

What is claimed is:

1. An adjustable chair comprising, in combination, a pair of cross-braced rear legs, a pair of standards, the lower portions of which constitute front legs, each one of said front legs being pivoted on the mating rear leg in X-fashion, cross-bracing members secured on the upper portion of said standards to constitute therewith a back for said chair, a seat member having its front edge pivoted on the upper ends of said rear legs, a pair of coaxial pins secured thereto and spaced rearwardly from the rear edge of said seat member, a longitudinal groove along the rear inner edge of each of said standards, a set of notches opening in the bottom of each of said longitudinal grooves, the notches of both standards being disposed pairwise at different horizontal levels and a pair of said notches receiving said pins to thereby removably articulate the rear edge of said seat member at different levels on said standards, a pair of elastic upright locking bars for said pins shaped soas to fit into saidlongitudinal grooves to conceal said grooves, notches and pins and to reconstitute the normal outline of said standards, said bars having their lower, ends secured on said front legs so that when stressed they insure the elastic locking of said pins in the pair of notches of any desired level and said bars being sufliciently yielding to permit shifting of said pins between the different levels of notches, a cross member connecting the upper ends of the locking bars and a latch means on one of the cross bracing members engaged with such cross member to hold the locking bars in locking position.

2. An adjustable wood chair according to claim 1, in which the cross member of the locking bars extends at a short distance from-a cross bracing member of the back of the chair andvin which the latch means is pivoted on said last-mentioned cross member and is brought into a locking position in which it prevents said cross member from being displaced rearwards.

References Cited in the file of this patent FOREIGN PATENTS 981,706 France Jan. 17, 1951 

